94 ICHTHYOPTERYGIA. 



medium remain in proximity to the left humerus, and these 

 show the general contour characteristic of this group. No 

 notch is, however, shown in the anterior border of the 

 radius ; but this may be due either to a disintegration of 

 the periphery of the bone or to its incomplete ossification, 

 — one of which conditions seems certainly to obtain. 



No history. 



R. 1166. Slab showing the ventral aspect of a large mandible appa- 

 rently belonging to this species ; from Lyme-Regis. The 

 splenial, which has been separated from the dentary, ex- 

 tends to the extremity of the mandible. Several detached 

 teeth are shown, the anterior ones having the long and 

 slender crowns characteristic of this species. The posterior 

 teeth are shorter, as in the type. Impressions of the 

 Lower Liassic Ammonites turneri are seen in the matrix. 



No history. 



28308. Slab showing a fragment of a cranium probably belonging 

 to this species ; from Lyme-Regis. A few of the charac- 

 teristic long-crowned teeth are preserved near the ex- 

 tremity. Purchased, 1853. 



Ichthyosaurus (?), sp. 

 The teeth of the general type of those of i". lonchiodon, but with 

 the crowns laterally compressed and indistinctly carinated. 

 Hob. Europe (England). 



It. 1342. Eragment of rock containing an imperfect tooth; from the 

 Rhsetic (Upper Triassic) bone-bed of Aust Cliff, near 

 Bristol. Both the root and the crown are fluted, the 

 former the more coarsely. 



Harford Collection. Purchased, 1888. 



Ichthyosaurus platyodon, Conybeare \ 



Syn. Ichthyosaurus chiroligostinus, Hawkins 2 . 

 Ichthyosaurus giganteus, Leach 3 . 



Cranial rostrum of medium length and stoutness ; premaxilla and 

 lachrymal uniting to exclude maxilla from nares ; supratemporal 

 fossa long and triangular. Superior border of articular raised above 



1 Trans. Geol. Soc. ser. 2, vol. i. pt. 1, p. 108 (1822). 



2 Memoirs'on Ichthyosauri, &c. pi. iii. (1834). 



3 Quoted by Owen in the Eep. Brit. Assoc, for 1839, p. 112 (1840). 



